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See detailLandscape-level thresholds and newt conservation
Denoël, Mathieu ULiege; Ficetola, G. Francesco

in Ecological Applications (2007), 17(1), 302-309

Ecological thresholds are defined as points or zones at which a rapid change occurs from one ecological condition to another. The existence of thresholds in species - habitat relationships has important ... [more ▼]

Ecological thresholds are defined as points or zones at which a rapid change occurs from one ecological condition to another. The existence of thresholds in species - habitat relationships has important implications for management, but the lack of concordance across studies and the wide range of methods used make generalizations difficult. We used two different statistical methods to test for the existence of thresholds for both individual species and the whole community, using three newt species as models. Based on a sample of 371 ponds, we found significant thresholds for both landscape configuration and composition. These were for the relationships between distance to forest and occurrence of Triturus alpestris and T. helveticus, and forest and crop cover and T. helveticus. Variability in the location of thresholds observed for the different species in this study caution against their use at the community level. Future studies should be based on the identification and assessment of thresholds for targeted species. Thresholds can be a useful concept from which tools may be developed to focus conservation effort for threatened species and their habitats. [less ▲]

Detailed reference viewed: 190 (21 ULiège)
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See detailLandscapes and landforms of Belgium and Luxembourg
Demoulin, Alain ULiege

Book published by Springer (2018)

Detailed reference viewed: 33 (1 ULiège)
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See detailHet landschap aan de overkant
Delhalle, Nancy ULiege

in Etcetera (2005), (97),

Detailed reference viewed: 6 (0 ULiège)
See detailLandslide characterization from space in the Rift flanks west of Lake Kivu (DRC)
Monsieurs, Elise ULiege

Poster (2016, December 13)

Detailed reference viewed: 22 (1 ULiège)
Peer Reviewed
See detailLandslide detection from remote sensing images using statistical and ANN classification methods
Danneels, Gaëlle; Havenith, Hans-Balder ULiege; Pirard, Eric ULiege

in Geophysical Research Abstracts (2007)

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See detailLandslide detection methods and inventory analysis applied to the Tien Shan, Kyrgyz Republic
Havenith, Hans-Balder ULiege; Danneels, Gaëlle; Strom, Alexander

in Geophysical Research Abstracts (2009)

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See detailLandslide Detection Methods, Inventory Analysis and Susceptibility Mapping Applied to the Tien Shan, Kyrgyz Republic.
Danneels, Gaëlle; Havenith, Hans-Balder ULiege; Strom, A. et al

in Proc. of the First World Landslide Forum (2008)

This paper presents results of the last five years of landslide detection and landslide susceptibility mapping in the Central and Southern Tien Shan. Landslide inventories have been compiled for areas of ... [more ▼]

This paper presents results of the last five years of landslide detection and landslide susceptibility mapping in the Central and Southern Tien Shan. Landslide inventories have been compiled for areas of major interest in the Kyrgyz Republic. For those areas, landslides were first mapped manually using KFA satellite images and aerial photographs. Recently, a landslide detection method has been developed in order to map landslides automatically. This method is based on a neural network scheme applied to detect particular slope failure features from remote sensing data. Multi-spectral and/or panchromatic ASTER and SPOT images as well as digital elevation models (DEMs) are used as inputs. This automatic method is designed to map medium-size mass movements (105-107 m3). This approach supplements the manual mapping of large slope failures and helps to complete the inventory of mass movements and related landslide susceptibility/hazard maps for large areas within the Tien Shan. Size-frequency analyses have been applied to the two existing regional landslide inventories. These size-frequency analyses revealed the incompleteness of the respective inventories (in the low-size domain) as well as regional and local differences due to natural and anthropogenic influences. To be able to perform reliable susceptibility and size-frequency analyses, the completed inventories need to be verified. At present, we perform local verification by manual mapping and control, but automatic verification methods are being developed. They will also allow us to determine the level of uncertainties. Ongoing research is focused on the propagation of uncertainties throughout the chain of processing. [less ▲]

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See detailLandslide hazard in the North Tanganyika - kivu rift zones: current knowledge and research perspective
Dewitte, Olivier; Albino, F; Delvaux, D et al

Poster (2013, November)

The North tanganyika – Kivu rift zones are areas naturally prone to landsliding where triggering and environmental factors that favour the occurrence of mass movement concentrate. In many places landslide ... [more ▼]

The North tanganyika – Kivu rift zones are areas naturally prone to landsliding where triggering and environmental factors that favour the occurrence of mass movement concentrate. In many places landslide hazard is very high, and anthropogenic factors such as land use change and urban expansion increase the sensibility to slope instability. From seismic to rainfall-induced mass movements we review the current knowledge of the various slope precesses and associated hazards that are present in these equatorial environments. A particular attention is given to urban areas such as Bukavu and Bujumbura where lanslide threat is particularly acute. Research perspectives on landslide inventorying, monitoring, and susceptibility and hazard assesment are presented. [less ▲]

Detailed reference viewed: 45 (3 ULiège)
See detailLandslide risk analysis in the Mailuu-Suu valley (Kyrgyzstan) by means of remote sensing techniques
Danneels, Gaelle; Pirard, Eric ULiege; Torgoev, Isakbek et al

in Geophysical Research Abstracts (2005)

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See detailLandslide risk reduction measures: a review of practices and challenges for the tropics
Maes, Jan; Kervyn, Matthieu; de Hontheim, Astrid et al

in Progress in Physical Geography (2017)

The overall objective of this review is to gain insights into landslide risk reduction measures that are applied or recommended in tropical landslide-prone countries, and the challenges at play. More ... [more ▼]

The overall objective of this review is to gain insights into landslide risk reduction measures that are applied or recommended in tropical landslide-prone countries, and the challenges at play. More specifically, this review aims to (i) presenting an overview of recent studies on landslides and landslide risk reduction in these countries, (ii) exploring the factors controlling the publication output on landslides and landslide risk reduction, (iii) reviewing the various landslide risk reduction measures recommended and implemented, and (iv) identifying the bottlenecks for the implementation of these strategies. A compilation of recommended and implemented landslide risk reduction measures in 99 landslide-prone tropical countries was made, based on an extensive review of scientific literature (382 publications). The documented measures are analysed Corresponding author: Jan Maes, Department of Earth & Environmental Sciences, KU Leuven, Celestijnenlaan 200E 03.256, Heverlee B-3001, Belgium. Email: maes.jan@kuleuven.be Progress in Physical Geography 1–31 ª The Author(s) 2017 Reprints and permission: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0309133316689344 journals.sagepub.com/home/ppg using a scheme of risk reduction measures that combines classifications of the Hyogo Framework for Action and the SafeLand project. Our literature review shows that the factors influencing the number of publications on landslides and landslide risk reduction per country are (in order of importance) the absolute physical exposure of people to landslides, the population number and the Human Development Index of a country. The ratio of publications on landslide risk reduction versus publications on landslides for landslide-prone tropical countries does not vary much between these countries (average: 0.28). A significant fraction (0.30) of all known landslide hazard reduction measures are neither implemented nor recommended according to our review. The most recommended landslide risk reduction component is ‘risk management and vulnerability reduction’ (0.38). However, the most implemented component is ‘risk assessment’ (0.57). Overall, the ratio of implemented versus recommended landslide risk reduction measures in the tropics is low (<0.50) for most landslide risk reduction components, except for ‘risk assessment’ (3.01). The most cited bottlenecks for implementing landslide risk reduction measures are scientific (0.30) and political (0.29) in nature. [less ▲]

Detailed reference viewed: 47 (8 ULiège)
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See detailA landslide susceptibility map of Africa
Broeckx, Jente; Vanmaercke, Matthias ULiege; Duchateau, Rica et al

Conference (2017, April 28)

Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial ... [more ▼]

Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial patterns of landslides and rockfalls on this continent is very limited. Also in global landslide susceptibility maps, Africa is mostly underrepresented in the inventories used to construct these maps. As a result, predicted landslide susceptibilities remain subject to very large uncertainties. This research aims to produce a first continent-wide landslide susceptibility map for Africa, calibrated with a well-distributed landslide dataset. As a first step, we compiled all available landslide inventories for Africa. This data was supplemented by additional landslide mapping with Google Earth in underrepresented regions. This way, we compiled 60 landslide inventories from the literature (ca. 11000 landslides) and an additional 6500 landslides through mapping in Google Earth (including 1500 rockfalls). Various environmental variables such as slope, lithology, soil characteristics, land use, precipitation and seismic activity, were investigated for their significance in explaining the observed spatial patterns of landslides. To account for potential mapping biases in our dataset, we used Monte Carlo simulations that selected different subsets of mapped landslides, tested the significance of the considered environmental variables and evaluated the performance of the fitted multiple logistic regression model against another subset of mapped landslides. Based on these analyses, we constructed two landslide susceptibility maps for Africa: one for all landslide types and one excluding rockfalls. In both maps, topography, lithology and seismic activity were the most significant variables. The latter factor may be surprising, given the overall limited degree of seismicity in Africa. However, its significance indicates that frequent seismic events may serve as in important preparatory factor for landslides. This finding concurs with several other recent studies. Rainfall explains a significant, but limited part of the observed landslide pattern and becomes insignificant when also rockfalls are considered. This may be explained by the fact that a significant fraction of the mapped rockfalls occurred in the Sahara desert. Overall, both maps perform well in predicting intra-continental patterns of mass movements in Africa and explain about 80% of the observed variance in landslide occurrence. As a result, these maps may be a valuable tool for planning and risk reduction strategies. [less ▲]

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See detailLandslide Susceptibility Mapping with Data Mining Methods—a Case Study from Maily-Say, Kyrgyzstan
Braun, A.; Fernandez-Steeger, T.; Havenith, Hans-Balder ULiege et al

in Engineering Geology for Society and Territory - Volume 2: Landslide Processes (2015)

Abstract: Multiple factors, such as geology, high mountain topography, seismic activity, climatic conditions and mining activities cause significant landslide hazard in the region around Maily-Say ... [more ▼]

Abstract: Multiple factors, such as geology, high mountain topography, seismic activity, climatic conditions and mining activities cause significant landslide hazard in the region around Maily-Say, Kyrgyzstan. To assess the landslide susceptibility a database containing landslide information and geological, morphological and hydrological parameters associated with landslide occurrence was established and analyzed with different data mining algorithms. The most promising results were achieved with an Artificial Neural ... [less ▲]

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See detailLANDSLIDE SUSCEPTIBILITY PREDICTION IN A MOUNTAINOUS CATCHMENT: THE NARANJO BASIN, WESTERN GUATEMALA
Estrada Orozco, Nick Kenner ULiege

Doctoral thesis (2017)

In tropical mountain areas, landslides triggered by heavy rainfall represent a natural hazard, especially where meteorological events such as tropical cyclones are recurrent. Rainfall-triggered landslides ... [more ▼]

In tropical mountain areas, landslides triggered by heavy rainfall represent a natural hazard, especially where meteorological events such as tropical cyclones are recurrent. Rainfall-triggered landslides may also increase in highly seismic active areas. This is the case of Guatemala, located in the Circum-Pacific Belt and between Pacific and Atlantic Oceans, sources of cyclonic events. Although Guatemala is a region where landslides are a widespread phenomenon, landslide inventories, maps and quantitative susceptibility assessments that are useful for land use planners and decision makers are hitherto non-existent. The aim of this research is to produce quantitative landslide susceptibility assessments, using logistic regression multivariate statistical method. The study area is a watershed located in the department of San Marcos (western Guatemala), impacted by a tropical storm event in October 2005. A total of 766 landslides were identified and mapped using orthoimages from 2005. Then, 99 landslides were mapped in 2011 based on field data. The main landslide type is shallow landslide (61 % in 2005), while 39 % of those landslides from 2005 evolved into debris flows. In total, susceptibility models using multivariate probabilistic approach were developed for shallow landslides, evaluating two different strategies for the sample size of non-landslides events and three different numbers of input variable in the models. Susceptibility models were developed for debris flows dataset and the union of both dataset (shallow and debris flows). The comparison of the models and the associated susceptibility maps highlighted 6 significant input variables that are associated with landslide occurences - elevation, slope, aspect, profile curvature, planform curvature and distance to roads. Performance comparisons of models were also carried out. To validate the performance of the model results, the ROC curve was used, as well as the four-fold and confusion matrix plots. A susceptibility map was generated to display the results of the models in terms of probability values. A proposal and discussion on the operational use of susceptibility maps where cutoff values can be chosen to define the lowest and highest landslide susceptibility were also made. These will help land use planners in decision-making and in implementing protective measures. [less ▲]

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See detailLandslide Susceptibility Zonation in case of deforestation in Northern Negros Natural Park (NNNP) - Philippines
Denis, Antoine ULiege

Master's dissertation (2006)

The Philippines is one of the most severely deforested countries in Southeast Asia with around 7 percent remaining forest in 2005. Moreover, due to its geographic circumstances, it is one of the most ... [more ▼]

The Philippines is one of the most severely deforested countries in Southeast Asia with around 7 percent remaining forest in 2005. Moreover, due to its geographic circumstances, it is one of the most natural hazard prone countries in the world with frequent occurrence of earthquakes, volcanic eruptions and typhoons, resulting notably in an increasing occurrence of landslides and flash floods. This work focuses on the North Negros Island and especially the recently proclaimed Northern Negros Natural Park (NNNP) that is considered the largest remaining evergreen forest in Negros Island and one of the largest in the Central Philippines. Deforestation continues to be a threat for this forest. The fact that this forest is located in mountainous area and that, due to a very high land pressure, people always creep higher to cultivate the steep slopes of these mountains, increase the landslide susceptibility associated with this deforestation. As an answer to that situation, this research aimed two main objectives. In a first time a land cover map was produced through digital classification of a 2003 SPOT 5 satellite image focusing on attempt for forest types differentiation in NNNP. Given that conventional method using spectral characteristics of the image revealed to be unsuccessful for this differentiation, this was finally achieved with the use of elevation and the distance to river as classifiers. The land cover map produced has an overall accuracy of 89,2 %. In a second time, a Landslide Susceptibility Zonation (LSZ) model was designed and implemented in a Geographical Information System (GIS) environment. The nine selected landslide-controlling factors were built from raw data and then combined through Weighted Linear Combination (WLC).Two scenarios corresponding to a “stable forest scenario” and a “deforestation scenario” were modeled. The integration of the land cover map previously produced served successfully as the key factor that enabled to model the Landslide Susceptibility (LS) change due to potential deforestation in NNNP. A sensitivity analysis of the factors used for this modeling was realized by comparison with a “LSZ in case of deforestation” map based on the four main factors only (land cover, land cover change, slope and proximity to river). It appeared that, the LSZ model was not sensitive to the use of other factors than these four main ones. Finally, in order to give an idea of the reliability of the results, the LSZ maps were compared with a landslide inventory realized during the field survey in North Negros. Some limitations in the landslide inventory did not allow drawing pertinent conclusion from this comparison. In parallel and in order to evaluate the feasibility of integrating the land cover knowledge of local environmentalist into a GIS data base through field survey and 3D-GIS activity in a remote laboratory, a participatory 3D-GIS experience was attempted in Negros. Consistence of results between field and 3D-GIS laboratory experience validate this way of extracting land cover information, which could revealed useful for land cover identification of hardly accessible areas. [less ▲]

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See detailLandslide Susceptibility, Hazard and Risk Mapping in Mailuu-Suu, Kyrgyzstan
Torgoev, Almazbek ULiege; Havenith, Hans-Balder ULiege

in Landslide Science and Practice (2013, October)

Detailed reference viewed: 31 (2 ULiège)
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See detailLandslides in Belgium: two case studies in the Flemish Ardennes and the Pays de Herve
Dewitte, O.; Van den Eeckhaut, M.; Poesen, J. et al

in Landscapes and landforms of Belgium and Luxembourg (2018)

Detailed reference viewed: 18 (2 ULiège)
See detailLANDSLIDES IN CENTRAL AFRICA: FROM DEFORMATION MECHANISMS TO EVOLUTION PROCESSES – CASES STUDIES FROM RWANDA AND BURUNDI
Draidia, Salah ULiege; Ndahimana, Hamuli; Habimana, Christophe et al

Scientific conference (2015, July)

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See detailLandslides in the Mailuu-Suu Valley, Kyrgyzstan - Hazards and impacts
Havenith, Hans-Balder ULiege; Torgoev, I.; Meleshko, A. et al

in Landslides (2006), 3(2), 137-147

Mailuu-Suu is a former uranium mining area in Kyrgyzstan (Central Asia) at the northern border of the Fergana Basin. This region is particularly prone to landslide hazards and, during the last 50 years ... [more ▼]

Mailuu-Suu is a former uranium mining area in Kyrgyzstan (Central Asia) at the northern border of the Fergana Basin. This region is particularly prone to landslide hazards and, during the last 50 years, has experienced severe landslide disasters in the vicinity of numerous nuclear waste tailing dams. Due to its critical situation, the Mailuu-Suu region was and still is the target area for several risk assessment projects. This paper provides a brief review of previous studies, past landslide events and a discussion on possible future risk scenarios. Various aspects of landslide hazard and related impacts in the Mailuu-Suu Valley are analyzed in detail: landslide susceptibility, historical evolution of landslide activity, size-frequency relationship, river damming and flooding as well as impacts on inhabited areas and nuclear waste storage zones. The study was carried out with standard remote sensing tools for the processing of satellite imagery and the construction of digital elevation models (DEMs). The processed inputs were combined on a GIS platform with digital landslide distribution maps of 1962, 1977, and 2003, digitized geological and geographic maps, and information from landslide monitoring and geophysical investigation. As a result, various types of landslide susceptibility maps based on conditional analysis (CA) are presented as well as predictions of future landslide activity and related damming potential and their possible impact on the population. For some risk scenarios, remediation and prevention measures are suggested. [less ▲]

Detailed reference viewed: 73 (4 ULiège)
See detailLandslides' mechanism and evolution in the western Rwanda
Draidia, Salah ULiege; El Ouahabi, Meriam ULiege; Dewitte, Olivier et al

Scientific conference (2016, January 27)

Landslides' mechanism and evolution in the western Rwanda Salah DRAIDIA1,*, Meriam EL OUAHABI1, Olivier DEWITTE2, Nathalie Fagel1, Hans Balder HAVENITH1 1 Institution 1 University of Liège Department of ... [more ▼]

Landslides' mechanism and evolution in the western Rwanda Salah DRAIDIA1,*, Meriam EL OUAHABI1, Olivier DEWITTE2, Nathalie Fagel1, Hans Balder HAVENITH1 1 Institution 1 University of Liège Department of Geology Street, n° 4000 Liège Belgium 2 Institution 2 Royal Museum of Central Africa Department of Geomogy Tervuren Belgium *Corresponding author: sdraidia@gmail.com, Département de Géologie, Quartier Agora, Allée du six Août, 14, B- 4000 LIEGE (Sart Tilman) Tel +32 0497351617 Keywords: mass movement, landslides, landscape evolution, geohazard,. Abstract The mass movement, and especially the instability of the soil and rocks, play a significant role in the changing aspect and the evolution of the landscape worldwide and particularly in tropical region. In Central Africa the landslides and others kind of instabilities are very frequent, important and represent a real threat for both population and economy. The case of Rwanda is remarkable, this country which is known as the country of thousand hills, is rich of various and very complex morphology caracterized by very steep slopes crossed by a dense network of watercourse, powered by a considerable amount of precipitation distributed in two wet seasons. The growing economy of the country brings a lot of project of infrastructures and mines and quarries exploitation (embankments and cuttings) which have a strong impact on the triggering of huge instabilities and so the modification of landscape. These instabilities and the intense activity of the rivers and streams could be considered as the engine who control the shaping and the remodeling of the landform. To understand the evolution process of these instabilities, and then the landscape change we started by the mapping of the instabilities using satellite images and then we went on the field to validate the inventory to identify the morphological aspect of the terrain, to refine our knowledge of the geological nature of the materials by sedimentological analyses on selected samples, and of course to try to better know the impact of the rock's weathering process leading to the constant modification of the landform. The computer-based quantitative analyses using GIS's data processing, were carried out to help to understand the distribution of the instabilities and the geomorphological phenomena observed to better connect and explain the whole information collected. The aim of the study is to bring in more than the mapping of instabilities a response about the process and the evolution of the instabilities and the factors impacting the phenomenon. [less ▲]

Detailed reference viewed: 62 (6 ULiège)